title: On ultrasound imaging for guided screw insertion in spinal fusion surgery.
abstract: Spinal fusion surgery generally involves the insertion of screws in the pedicle, a three-dimensional (3-D) process that requires great skill if serious consequences are to be avoided. This article describes an image guidance technique based on generating B‑mode images from within a small bore hole in the pedicle's trabecular bone. The purpose is to determine the viability and safety of the hole placement for subsequent insertion of the screw. Toward this end, this article endeavours to understand the factors that govern B-mode image quality. Specifically, the results of numerical simulations on the effects of transducer frequency and bone volume on image quality are presented along with demonstrations of B-mode image formation obtained in vitro on human pedicles using a 3.2 MHz probe. The results of the numerical simulations suggest that high frequency and high bone volume generally reduce the image quality. The in vitro experiments showed that the trabecular and cortical bone can be detected in the B-mode images.
authors.affiliation: Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Canada.
authors.forename: Al-Hassan
authors.initials: AH
authors.lastname: Aly
authors.forename: Howard J
authors.initials: HJ
authors.lastname: Ginsberg
authors.forename: Richard S C
authors.initials: RS
authors.lastname: Cobbold
mesh_terms: D001863:Bone Screws; D006801:Humans; D019919:Prosthesis Implantation / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013123:Spinal Fusion / Q000295:instrumentation* / Q000379:methods*; D025321:Surgery, Computer-Assisted / Q000379:methods*; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging* / Q000601:surgery*; D014463:Ultrasonography / Q000379:methods*